1. Field
The present invention refers to an actuator adapted to operate in environments having a combustible atmosphere such that special precautions are required when using electric, pneumatic, or mechanical devices.
2. Related Art
In an environment with explosion risks, an actuator must be able to withstand the explosion force that is characteristic for any given gas or mixture according to the degree of risk associated with the type of atmosphere in which the actuator itself operates.
Conventional methods provide several deflagration-protecting procedures for providing an actuator, where each procedure aims to insulate actuator components that are prone to explode. In some cases, deflagration protection is realized by encapsulating critical actuator parts in a suitable vessel. The suitable vessel is further equipped with outlets for connecting mechanical parts that are used for the connection of mechanical parts that transit mechanical power and outlets used for connecting at least one of an electric supply and control connections.
The geometric shape of the vessel, the volume ratio occupied by the internal components with respect to the internal volume of the housing containing them, and the degree of uniformity of the free volume are some of the design variables whose optimisation affects both the static response and the dynamic response of the actuator to an explosion. With respect to a possible detonation phenomenon, it is good practice to keep the free volume uniform inside the vessel, thereby avoiding the occurrence of precompression phenomena that follows detonation. Generally, however, this practice allows realization of a device that is scarcely appreciated because of excessive overall dimensions that impair placing the device in locations having limited available space.
An object of the present invention is to solve the above prior-art problems by providing an anti-deflagrating operating actuator, adapted to operate in an environment that is classifiedxe2x80x94according to the existing standards, as having a maximum explosion risk. An actuator as such comprises the following:
components supplied with an electric voltage, a gear reducer, and at least one of a motion transmitting mechanism and a mechanism transforming the motion from rotary to linear, are integrally protected against deflagration;
an external housing that optimally protects the apparata contained therein, and is formed such that the shape of the housing outlines the internal parts, guarantees final reduced volume and weight, keeps an internal five volume uniform, and guarantees to reduce or eliminate a detonating effect;
ergonomically placed outlets for connecting mechanical parts that transmit the mechanical power and guaranteeing easy actuator installation next to walls;
outlets for connecting at least one of the electric supply and control connections, wherein the outlets are positioned so they do not interfere with the wiring resistance by kinking and stretching the electrical wiring;
an angular-operating actuator in which the motion is transmitted directly to an external user via an intermediate connection shaft and a reducer shaft located in the housing.
The above and other objects and advantages of the invention, as will appear from the following description, are obtained by an actuator as claimed in claim 1. Preferred embodiments and non-trivial variations of the present invention are claimed in the dependent claims.